Comment by stan_rogers

When you consider that (probably) most of the people who exhibit serious substance abuse problems are self-medicating, the numbers aren't difficult to digest. (I say this not as somebody with studies in hand, but as a person who's been clean and sober for more than a quarter-century, and who has significant experience dealing with other addicts and alcoholics. One can make pretty reliable predictions about underlying issues based entirely on the addict's "drug of choice".)